These 2 creatures are quite different. One of the differences is that filter feeders filter the water for food particles, while the fluid feeders feed on liquid like blood. Filter feeders are a sub-group of suspension feeding animals that feed by straining suspended matter and food particles from water, typically by passing the water over a specialized filtering structure. Fluid feeders are organisms that feed on the fluid of other organisms. It can refer to: Hematophagy, feeding on blood. Nectarivore, feeding on nectar. Plant sap feeders.